Harry Potter freak Evanna Lynch, 15, steals the spotlight in her silver-screen debut as Hogwarts space cadet Luna Lovegood in the highly anticipated film “Harry Potter and the Order of the Phoenix,” which opens July 11.

Lynch’s spot-on portrayal of the eccentric outcast in the fifth Harry Potter flick cast a spell over the crowd at a screening last week and is sure to capture the hearts of fellow fans all over the world.

Author J.K. Rowling, who penned the absurdly popular Harry Potter series, is already impressed. On her Web site, Rowling said “there is only one possible thing to say” about the young actress: “Perfect.”

Lynch, a diehard Potter fan since age 8 who grew up in Termonfeckin, Ireland, has always had a connection with Luna, immediately loving the character when she first appeared in the book “Order of the Phoenix.”

“I loved her disarming honesty, her unassuming wisdom and her innocent purity,” Lynch told The Post. “She has no masks or insecurities. She simply is.”

Lynch, an avid fan of the Potter films who “quite enjoyed acting,” dreamed of playing Luna on the big screen.

She “was not happy to just sit and wait for date to take its course,” so she recruited some friends to play fellow Hogwarts students, made tapes of herself playing Luna, and sent them to casting agents at Warner Bros.

“In the end, the tapes came to nothing,” said the Lynch, who has waited in line for Potter books, routinely reads fan sites such as The Post’s Potter blog and has a cat named Luna. “But it is still a cool fact that we made them.”

Lynch even sent a letter to Rowling telling her how much she wanted to play Luna, but feared it would never happen because she was from a “humble village where not much happened.” She got a handwritten letter back.

“I was overjoyed,” Lynch said. “She told me that she also came from a sleepy little village, so how could that not give me hope? Of Termonfeckin, she also said, ‘At least it has a great name.’ ”

“I read that letter to death and I still do,” she said. “I carry them with me in my handbag always.”

Lynch eventually got her opportunity to try out for Luna at an open casting call – along with 15,000 other girls.

“I loved Luna as much as anyone could,” she said. “I knew that I had just as much of a chance as anyone else there.”

Lynch nailed the audition and got the part.

She said she is “extremely grateful” that Rowling, whom she got to meet in March 2006, has divulged some secrets about Luna’s future to help her play the part, but is glad she hasn’t shared too much before the last Potter book’s July 21 release.

“I wouldn’t want to know before anyone else,” she said. “I think that would be like Christmas coming early.”